sqlite-ulid by asg017

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A SQLite extension for generating and working with ULIDs. Built on top of sqlite-loadable-rs and ulid-rs.

If your company or organization finds this library useful, consider supporting my work!


.load ./ulid0

select ulid(); -- '01gqr4j69cc7w1xdbarkcbpq17'
select ulid_bytes(); -- X'0185310899dd7662b8f1e5adf9a5e7c0'
select ulid_with_prefix('invoice'); -- 'invoice_01gqr4jmhxhc92x1kqkpxb8j16'
select ulid_with_datetime('2023-01-26 22:53:20.556); -- '01gqr4j69cc7w1xdbarkcbpq17'
select ulid_datetime('01gqr4j69cc7w1xdbarkcbpq17') -- '2023-01-26 22:53:20.556'

Use as a PRIMARY KEY for a table.

create table log_events(
  id ulid primary key,
  data any

insert into log_events(id, data) values (ulid(), 1);
insert into log_events(id, data) values (ulid(), 2);
insert into log_events(id, data) values (ulid(), 3);

select * from log_events;
│             id             │ data │
│ 01gqr4vr487bytsf10ktfmheg4 │ 1    │
│ 01gqr4vr4dfcfk80m2yp6j866z │ 2    │
│ 01gqr4vrjxg0yex9jr0f100v1c │ 3    │

Consider using ulid_bytes() for speed and smaller IDs. They generate about 1.6x faster than ulid(), and take up 16 bytes instead of 26 bytes. You can use ulid() to create a text representation of a BLOB ULID.

create table log_events(
  id ulid primary key,
  data any

insert into log_events(id, data) values (ulid_bytes(), 1);
insert into log_events(id, data) values (ulid_bytes(), 2);
insert into log_events(id, data) values (ulid_bytes(), 3);

select hex(id), ulid(id), data from log_events;
│             hex(id)              │          ulid(id)          │ data │
│ 0185F0539EBF286DA9F56BA4D9981783 │ 01gqr577nz51ptkxbbmkcsg5w3 │ 1    │
│ 0185F0539EC54F85745C1ECB64DF3A97 │ 01gqr577p59y2q8q0ysdjdyemq │ 2    │
│ 0185F0539ED48113F6F67BF3F6A4BFF7 │ 01gqr577pmg49zdxkvyfva9fzq │ 3    │

Extract the timestamp component of a ULID with ulid_datetime().

select ulid_datetime(ulid()); -- '2023-01-26 23:07:36.508'
select unixepoch(ulid_datetime(ulid())); -- 1674774499
select strftime('%Y-%m-%d', ulid_datetime(ulid())); -- '2023-01-26''

Consider using ulid_with_prefix() to generate a text ULID with a given prefix, to differentiate between different ID types.

select ulid_with_prefix('customer'); -- 'customer_01gqr5j1ebk31wv30wgp8ebehj'
select ulid_with_prefix('product'); -- 'product_01gqr5prjgsa77dhrxf2dt1dgv'
select ulid_with_prefix('order'); -- 'order_01gqr5q35n68jk0sycy1ntr083'

Quick benchmarks

Not definitive, hastily ran on a Macbook, not representative of real-life usecases. The uuid() SQL function comes from the official uuid.c extension.

Test case Time
generate_series() to generate 1 million rows 28.5 ms ± 0.8 ms (1x)
Calling ulid_bytes() 1 million times 88.4 ms ± 2.8 ms,, 3.10 ± 0.13 slower
Calling uuid() 1 million times 141.6 ms ± 1.5 ms, or 4.97 ± 0.15 slower
Calling ulid() 1 million times 344.3 ms ± 11.9 ms, or 12.07 ± 0.53 slower

So ulid_bytes() is pretty fast, but returns an unreadable blob instead of a nicely formatted text ID. The ulid() function does that, but is more than twice as slow than uuid().

However, generating 1 million ulid() IDs in ~350ms is most likely "good enough" for most SQLite usecases.

Using with...

Language Install
Python pip install sqlite-ulid PyPI
Datasette datasette install datasette-sqlite-ulid Datasette
Node.js npm install sqlite-ulid npm
Deno deno.land/x/sqlite_ulid deno.land/x release
Ruby gem install sqlite-ulid Gem
Rust cargo add sqlite-ulid Crates.io
Github Release GitHub tag (latest SemVer pre-release)

The Releases page contains pre-built binaries for Linux x86_64, MacOS, and Windows.


For Python developers, install the sqlite-ulid package with:

pip install sqlite-ulid
import sqlite3
import sqlite_ulid
db = sqlite3.connect(':memory:')
db.execute('select ulid()').fetchone()
# ('01gr7gwc5aq22ycea6j8kxq4s9',)

See python/sqlite_ulid for more details.


For Node.js developers, install the sqlite-ulid npm package with:

npm install sqlite-ulid
import Database from "better-sqlite3";
import * as sqlite_ulid from "sqlite-ulid";

const db = new Database(":memory:");

See npm/sqlite-ulid/README.md for more details.


For Deno developers, use the deno.land/x/sqlite_ulid module:

import { Database } from "https://deno.land/x/sqlite3@0.8.0/mod.ts";
import * as sqlite_ulid from "https://deno.land/x/sqlite_ulid@v${VERSION}/mod.ts";

const db = new Database(":memory:");

db.enableLoadExtension = true;

const [version] = db.prepare("select ulid_version()").value<[string]>()!;



And for Datasette, install the datasette-sqlite-ulid plugin with:

datasette install datasette-sqlite-ulid

See python/datasette_sqlite_ulid for more details.

As a loadable extension

If you want to use sqlite-ulid as a Runtime-loadable extension, Download the ulid0.dylib (for MacOS), ulid0.so (Linux), or ulid0.dll (Windows) file from a release and load it into your SQLite environment.

Note: The 0 in the filename (ulid0.dylib/ ulid0.so/ulid0.dll) denotes the major version of sqlite-ulid. Currently sqlite-ulid is pre v1, so expect breaking changes in future versions.

For example, if you are using the SQLite CLI, you can load the library like so:

.load ./ulid0
select ulid_version();
-- v0.1.0

In Python, you should prefer the sqlite-ulid Python package. However, you can manually load a pre-compiled extension with the builtin sqlite3 module:

import sqlite3
con = sqlite3.connect(":memory:")
print(con.execute("select ulid_version()").fetchone())
# ('v0.1.0',)

Or in Node.js using better-sqlite3:

const Database = require("better-sqlite3");
const db = new Database(":memory:");
console.log(db.prepare("select ulid_version()").get());
// { 'ulid_version()': 'v0.1.0' }

With Datasette, you should prefer the datasette-sqlite-ulid Datasette plugin. However, you can manually load a pre-compiled extension into a Datasette instance like so:

datasette data.db --load-extension ./ulid0


I (Alex 👋🏼) spent a lot of time and energy on this project and many other open source projects. If your company or organization uses this library (or you're feeling generous), then please consider supporting my work, or share this project with a friend!

See also